"There is a holder that's attached to the wall with mounting tape and the doorbell button goes inside," said Jin. "The design of it has training in mind. You can put a treat inside the space behind that initiates the dog to be interested in this."

He said the dog eventually learns to push the bell every time they want to be let out, or come back into the house.

"I tried probably for a year or so just to refine it and now got to this point where it's easy to train, easy to install." he said.

The kit comes with two doorbells, one for inside the house and one for outside. It also comes with small ringers that can be placed anywhere around the house. Since they are portable, the doorbells can be adjusted to accommodate any size dog.

The total cost? Around $55 to get the set - an indoor and outdoor Doggie Doorbell.

Jin has sold a few to friends and family and now he's finally ready to launch his business off the ground. Starting a fund-raising campaign where people can pre-order the doorbells to kick-start business.

"We have gone quite a long ways where we're ready to do the first batch of production so with some pre-orders, the funds will help to finish the tooling, getting the first orders in place."

He said he's received such a good response to the product, they're even thinking about making cat doorbells too.

"Cats can use this. I think eventually we'll make a version especially for cats ... that's easier to train for cats." said Jin.

So the next time you want to know if your dog, or cat needs to do its business, just listen for the doorbell.